Energy Star Entry Doors and Windows


A lot of businesses talk about the benefits of an ENERGY STAR rated door or window. Few, however, explain what that means or what criteria are used to determine if a product is actually an ENERGY STAR rated product.

Below are the product criteria for ENERGY STAR qualified windows, doors, and skylights. A product must meet all of the identified criteria to be labeled as ENERGY STAR qualified by its manufacturer.

  1. Definitions:
    • Window: An entire glazed unit designed for a vertical installation in an external wall of a residential building to allow for views and natural day lighting. May be fixed or operable.
    • Door: A residential entry or patio door system including door leaf, frame, and lites, where applicable.
    • Entry Door: An exterior door other than glass doors.
    • Window, door and skylight components: Components used in the construction of a qualified window, door, or skylight including, but not limited to, coated glass, frame profiles, and warm edge spacers.
    • Private labeler: A company that markets under its own name windows, doors, or skylights manufactured by a different company that is an ENERGY STAR for Windows, Doors, and Skylights PARTNER.
    • U-Factor: The rate of non-solar heat loss or gain through a material or assembly. Expressed here in units of Btu/h·ft2·ºF.
    • Solar Heat Gain Coefficient (SHGC): The fraction of solar radiation admitted through a window, door, or skylight. Expressed as a value between 0 and 1.
    • NFRC 1997 Procedures: Product testing and simulation procedures officially released by NFRC in 1997, which provided residential and commercial ratings for each product based on two distinct product test sizes.
    • NFRC 2001 Procedures: New product testing and simulation procedures officially released by NFRC in 2001, which provide more accurate ratings of products and specify a single standard test size for each product type.
    • RES97 rated at 90 degrees: NFRC 100 1997 procedures rated skylights at a 90 degree angle, generating a lower reported U-Factor than the same skylight rated under the NFRC 2001 procedures. RES97 rated skylights may be present in the marketplace until March 31, 2008. NFRC labels for products using this procedure state: “RES97 rated at 90 degrees.”
    • ENERGY STAR Climate Zone: See ENERGY STAR Climate Zone Map. A complete list of ENERGY STAR Climate Zones by state, county and city is available from the Partner Resources section of ENERGY STAR for Windows, Doors, and Skylights web pages accessible via or from DOE or its contractor.
  2. Eligible Products: Windows, doors (including entry and patio), and skylights (including tubular daylighting devices) that meet the definitions specified above and testing, certification, and ENERGY STAR qualification criteria specified below.
  3. Testing and Certification Criteria: The performance of windows, doors, and skylights must be independently tested and certified in accordance with National Fenestration Rating Council (NFRC) procedures for U-Factor (NFRC 100) and Solar Heat Gain Coefficient (NFRC 200). Products may be rated under either the NFRC 1997 or NFRC 2001 procedures.
  4. Effective Date: The date that a manufacturer may begin to qualify products as ENERGY STAR will be defined as the effective date of the Partnership Agreement, unless a later date has been specified (i.e., Equivalent Energy Performance Amendment). This most recent version of the Program Requirements, Version 3.0, supersedes all previous versions.
  5. Future Criteria Revisions: ENERGY STAR reserves the right to change the specification should technological and/or market changes affect its usefulness to consumers, industry, or the environment. Keeping with current policy, industry/stakeholder discussions determine revisions to the criteria.
  6. ENERGY STAR Criteria: To qualify in each ENERGY STAR Climate Zone products must have NFRC certified U-Factor and, where applicable, Solar Heat Gain Coefficient (SHGC) ratings at levels which meet or exceed the minimum qualification criteria specified in Table 1 and the ENERGY STAR Climate Zone Map on the following page.Equivalent Energy Performance Amendment (effective September 19, 2005): Allows windows and doors with energy performance equivalent to the prescriptive criteria to qualify in the Southern and South/Central climate zones, excluding California. Equivalent performance criteria are not applicable to the Northern and North/Central climate zones or to skylights.Skylights: Ratings produced under NFRC 1997 or NFRC 2001 may both be used to qualify window and door products for ENERGY STAR. Skylights rated using NFRC 2001 procedures must meet the “2001 NFRC rated at 20 degrees” skylight U-Factor qualification criteria. Skylights rated using NFRC 1997 procedures must have ratings for the residential test and simulation size (RES97) that meet the “RES97 rated at 90 degrees” skylight U-Factor qualification criteria.